Pulsator for milking machines



Aug. 29, 1933. J. L. HULBERT PULSATOR FOR MILKING MACHINES Filed July 2, 1929 fill/lll# "Iv a.

Patented Aug. 29, 1933 UNITED STATES 1,924,931 n PULsA'roR Fon MIILKING MACHINES John L. Hulbert, Poughkeepsie, N.` Y., assigner to The De Laval Separator Company, New York, N. Y., a corporation of New JerseyY Application July 2, 1929. Serial'rNo. 375,356"

5 claims. (o1. 31-6fn In applications filed by C. H. Hapgood, November 1'7, 1926, Serial No. 148,787, and December 24, 1927, Serial No. 242,329, there is set forth an electrically operable pneumatic pulsator for milling machines comprising a casing mounted on a milk and enclosing a pulsation or valve chamber having a port communicating with a Source of vacuum, a port communicating with a tube in which the pneumatic pulsations are to be Y produced, and a port, opposite the rst named port, communicating with a passage formed by the hollow core of an electro-magnet. This passage communicates with a source of high pressure,

v, conveniently the atmosphere. Between the ports is a combination armature and valve in the shape of a magnetizable disc, which, when the magnet is not energized, is forced by atmospheric Vpressure against the vacuum port and which, when Y the magnet isenergized, is pulled ofi the vacuum port and drawn against the Aatmospheric port. Thereby the atmospheric port and vacuum port are alternately brought into communication with the pulsation pipe, producing pneumaticpulsations.

In practice the device is operative, but the armature-valve is not always instantly responsive.

to the unbalanced air pressure when the magnet is ele-energized, the valve sometimes sticking and causing delayed or uncertain action. I have discovered that this action is due to residual magnetism and have also discovered that the diiculty may be overcome by substantially increasing the area that is exposed to` atmospheric pressure. In the preferred embodiment ci the invention, this r increased pressure area is provided by counterboring the magnet pole face concentrically to the hollow core oi" the magnet, sothat the circular valve seat formed by the magnet pole will be of so great a diameter relative to the diameter of the air passage enclosed by the hollow core of the magnet that the difference between the absolute pressures on Vopposite sides of the armature will, when the magnet is cle-energized, render residual magnetism ineffective to cause ysticking of the armature-valve and enable the durations of the periods during which the pulsation pipe is connected with air and vacuum to be more accurately and certainly predetermined.

The figure of the drawing is a vertical sectional lView through the pail top, vacuum chamber, Vacuum tube, magnet, armature-valve and the tubes intended for direct or indirect connection with the teat cups.

On the pail tcp a is mounted a casing which 'enclcses a vacuum chamber b opening to a tube c adapted to connect with a source of vacuum and having a nozzle d which has a tube connection, either directly or through a claw, with the milk chambers of a set of teat cups. In the casing is also formed a pulsation or valve chamber e having a' control port f opening to the vacuum. chamber b andA a nozzle g which has a tube connection either direct with the pulsationchambers thi: teat cups, Aor with an udder pulsator, as shown in said I-Iapgood applications. On the casing is mounted an electro-magnet h having a hollow core rorining a passage that communicates with the atmosphere. Air passage i preferably aligns withvacuum port f, and between this passage and port, that is, between the magnet and the partition separating vacuum chamber b from valve chamber c, is a disc lc, which is the armature the magnet and at thesame time serves as a valve which, when lifted by the magnet, opens vacuum` port f and closes air passage z' and which, when released by the magnet, is moved by unbalanced pneumatic pressure, assisted by gravity, to open air passage z' and seat against and close vacuum port f. l v Y The pole face of the magnet iscounterbored at m, thereby greatly enlarging the area subjectto constant atmosphericpressure.A Practically, the area of the counterbore is such that, if multiplied by the unit difference in pressure betweenthe two'sides ofl thedisc when in contact with the pole` face, the force produced will be greater than that required t0 overcome the pullon the disc by residual magnetism in the magnet.

To illustratezthe application of this` formula, let it be assumed that- A=area of valve face exposed to higher pressure=.196 sq. inches.

Rzpull of residual magnetism=13-1 ounces P=high pressure=l14-7 lbs.=235 oz. per sq. in. p=low pressure=7.3 1bS.=1v17 ozjper sq. in. 'M=total magnetic'pull when valve is on air port=96 oz.

Another way of expressing the formula is that the area of the .valve face exposed to the higher pressure is greater than the pull of the residual magnetism divided by the difference .in unit pressure operativepon opposite sides Y,of the armature valve.

Then A In operation, atmospheric pressure entering through passage i forces the armature-valve lc CTI against the valve seat surrounding vacuum port f, and air at atmospheric pressure hows into pipe g. When an electric impulse energizes magnet h, it draws armature-valve 7c off the seatraround vacuum port f and against the seat around the enlarged end of passage i, shutting off the inlet from the atmosphere, causing air to be drawn through pipe g, valve chamber e and port ,f into vacuum chamber b. When the electric current is broken, residual magnetism in the core of the magnet tends to retain the armature-valve k on its upper seat, but atmospheric pressure acting on the surface exposed to the large area port formed by the counterbore m immediately overcomes this force and drives the armature-valve k down against the seat around vacuum port f, thus opening the air inlet, and closing the vacuum connection, to pipe g.

Having now fully escribed my invention, what I claim and desire to protect by Letters Patent is:

l. In a milking machine, the combination with a milk pail and a pulsation pipe in which it is desired to produce pneumatic pulsations of denite duration, of means on the pail forming a vacuum chamber adapted to vcommunicate ,with a source of suction and with the interior of the pail and having a port adapted to communicate with the pulsation pipe, an intermittently operable electro-magnet and means providing a passage adapted to communicate with a source of higher pressure and adapted to communicate with said pulsation pipe, an armature valve positioned between said port and passage and adapted to be moved, by the greater pressure through said passage, to close said port and to be moved against said greater pressure by the magnet, when energized, vto make direct contact with the magnet pole and close said passage, the area` of the armature valve face Iexposed to said higher pressure being greater `than the pull of the residual magnetism divided by the dlierence in unit-pressures operative oniopposite sides of the armature valve, so that, when the magnet is dez-energized, the residual magnetism will be ineffective to resist the actuation of said valveY by said higher pressure. l i Y 2. In a milking machine, the combination with a pulsation pipe and a milk pail, of means on the pail forming a vacuum chamber adapted to communicate with a source of suction and with the interior or" the pail and having a port adapted to communicate with the pulsation pipe, an intermittently operable electro-magnet provided with a passage communicating with a source of higher pressure and adapted to communicate with said pulsation pipe, and an armature valve` positioned between said passage and port and adapted to be moved, bythe greater pressure through face being counterbored to provide an area'on the face of the armature valve exposed to said higher pressure multiple times as great as the area of a cross-section of said passage and greaterv than the pull of the residual magnetism divided by the difference in unit pressure operative on opposite sides of the armature valve, so that, when the magnet is cle-energized, the residual magnetism will be ineiective to prevent the prompt movement of the armature valve to open said passage and close said port.

3. In a milking machine, the combination of a casing forming a pulsation chamber and provided With a low pressure port, a magnet having one pole against which the hereinafter mentioned armature is adapted to directly seat, said magnet being hollow to afford a high pressure passage, and an armature-valve positioned in said chamber between said ports, the magnet pole face having a counterbore providing an air exit port from said passage Whose area is greater than the pull of the residual magnetism divided by the difference in unit pressures operative on opposite sides of the armature-valve.

4. In a milking machine, the combination 'with an electro-magnet and means forming a pulsation chamber provided with a suction port and a port communicating with a source of higher pressure, of an armature valve positioned in the chamber between said ports and adapted to normally seat on the suction port and to be Withdrawnl therefrom and seat direct on the magnet pole and close the pressure port by excitation of the magnet; the area of the armature-valve face exposed to said higher pressure being greater than the pull `of the residual magnetism divided by the diierence in unit pressures operative on opposite sides of the armature-valve.

5. In a milking machine, the combination with a pipe in which pneumatic pulsations are to be produced, of anelectro-magnet having one pole adapted to serve as a valve seat and which encloses aipassage adapted to convey a pressure iiuid vtherethrough to said pulsation pipe, a disc adapted to ymake direct contact with the magnet pole and to function as a magnet armature and also as aivalve and which is exposed on one face to the pressure of said fluid, means to expose the oppositeface of the valve to a substantially lov-ler pressurewhereby the higher pressure tends to force said valve oi said seat, the strength of said magnet being such that, when energized, it will pull said valve onto its seat against said pressure, the area oi the surface exposed to said higher pressure vbeing greater than. the pull of the residual magnetism divided by the difference in unit pressures operative on opposite sides of the armature-valve so that, said pressure uid will immediately ovecome the residual magnetism of the magnet when the latter is de-enerized.

J L. HULBERT. 

